EXPERIMENTAL INVESTIGATION OF HEAT FLUX FLUCTUATIONS ON THE REAR COVER OF A PLANETARY PROBE ENTRY-CONFIGURATION

Abstract

To develop effective thermal protection systems for planetary probes to enter the planet’s atmosphere, it is important to be able to simulate the thermal loads with sufficient confidence. Although the convective thermal loads in the base region of blunt capsule configurations are orders of magnitude less compared to the frontshield values, the criticality in this region arise from the great uncertainties of the prediction. The challenge is to capture the influence of the highly complex flow field in the base area, both, in experiments as well as in simulations. This flow field enforces convective heat loads along the rear cover surfaces which are expected to be highly time-dependent. This paper describes the results of a wind tunnel test campaign focused on the experimental detection of heat flux fluctuations in the rear cover of a planetary probe. The ExoMars Entry, Descent and Landing Demonstrator Module (EDM) was chosen as reference configuration to enable comparison to previous experimental and numerical results. Tests were conducted at two different hypersonic inflow conditions, three different angle of attacks and different roll angles to enable a sensitivity study. Several measurement techniques, capable of capturing heat flux fluctuations in different frequency-domains, from low-, mid- to high-frequency content, were applied.